Bowl vent check valve



Jan. 12, 1960 I T. D. SPRAGLE BOWL VENT CHECK VALVE Filed Nov. 13, 1957 8 20 l7 3 i, f

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7 30 I 26 32 5/ l 4/ I INVENTOR. THOMAS D. SPRAGLE MHWZW ATTORNEY United States PatentfO F BOWL VENT CHECK VALVE Thomas D. Spragle, St. Charles, Mo., assignor to ACE Industries, Incorporated, New York, N.Y., a corporation of New Jersey Application November 13,1951, Serial No. 696,171 '5 Claims. c1. 261-42) the; passage of a fue1-and-air mixture vto the engine. Air

isrdrawn into the engine through an air horn which forms part of the mixture conduit ofthe carburetor- ,A slight drop below atmospheric pressure occurs asair is drawn through an air cleaner attached to the air horn. Mounted in .the mixture conduit of the carburetor is .a throttle valve which opens and closes responsive to demands for increased or decreased engine power, respectively. During idleoperation of the engine, the throttlevalve is substantially closed and the flow of air through the mixture conduit'is substantially less than the flow during normal operation. During idle a. high suction exists downstream from the closed throttlevalve, and a relatively low suction exists upstream from the throttle-valve,;as in the .air horn, drawing a small quantity ofair from the .air horn and past the throttle valve. Generally, a carburetor is provided with a fuel. reservoir from which fuel is drawn into the mixture conduitresponsive to engine.requirement. To avoid a pressure differential in the air-horn and. inthe fuel. reservoir,.a passage, known as .a balance tube,-.or vent, is provided therebetween. When an engine is hot, the fuelin the. reservoir normally vaporizes and creates a pressure therein. through the passage to the air horn. During idle operation, very little air passes through the air horn because the .throttle .is .closed and the fuel vapors passing into the :air horn create-ian overly rich mixture as the air and fuel vapors from the air horn .mix'with the normal quantity of idle fuel and enter .the engine. Such undue richness causes a rough idle. Various .methods are known or under consideration for correcting such rough, hot idle conditions, and some of these methods are relatively successful.

This invention is directed to eliminating a rough, hot idle by preventing'fuel vapors in the reservoir from entering the air horn of a carburetor during idle operation by providing a check valve in the passage between the fuel reservoir and the air horn. The check valve is closed during idle operation and opens during normaloperation of the carburetor responsive to an increase in suction in the air horn.

It is therefore an object of this invention to improve the hot idle characteristics of a carburetion system.

Another object of this invention is to" eliminate hot, rough idle conditions in a carburetion system, in an improved and simplified manner; by preventing fuel vapors from entering the air hornofthe carburetor operation.

Thispressure is :relieved during idle 2,920,877) ,Ratented Jan. 12,1960

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Additional objects and advantages will be apparent from the following description and drawings, inwhich:

Fig. 1 is a partial fragmentary elevation view of an embodiment of the invention during hot idle operation.

Fig. 2 is an enlarged sectional view illustrating a check valve shown in Fig. 1 during normal or high-speed operation. A

Fig. 3 is an enlarged sectional view of the checkvalve shown in Figs.-l and 2.

Fig. 4 is atop view ofFig. -3.

Referring to Fig. 1, the carburetorincludes a base or flange 1 for attachment to the intake manifold of an engine, a'body 2, and a coverfi. The flange, body and cover arenormally secured together as by bolts 4. mixture conduit 7 passes through the flange, body, and cover, and includes an air horn 8 in the cover 3. Secured to the air horn is an air cleaner 9. i A conventional choke valve 11 is mounted in the air horn 8. The choke Valve is fixed to a rotatable shaft 12 passing through opposite walls of the air horn-'8. Rotatably mounted ,on' the shaft is a lever 14 having fixed thereto a lug 15 to which a manual control cable may be attached. Fixed to the shaft is an arm 17 having a finger 18 received between a pair ofstops-19 on the lever. A spring 20 engages the lever 14 and the arm 17 urging the choke closed while permitting slight opening for breathing of the engine when the choke is manually positioned in its closed position. Fuel enters the carburetor from a source of supply through an inlet 25 and passes into a fuel reservoir z fi'. The level of the 'fuel in the chamber is controlled by a conventional float 27 and related needle valve assembly. The carburetor is provided with conventional fuel systems including a main fuel orifice 30 and a metering rod-'31 opening into a main fuel passage32 leading to a fuel nozzle 33 which discharges into a venturi clu s'terj36 in the mixture conduit 7. As illustrated, the carburetor is provided with an anti-percolating system 37 including a restricted orifice 38 opening into the air horn 8L .An idle system originates in an idle tube 40 Which draws'fuel from the main fuel passage '32 and terminates in ,an idle port 41 and adjustable idle orifice-42 through which the flow of fuel is controlled by an adjustable needle 43. The carburetor is normally provided with a pump circuit (not shown) for providing additional fuel during .the transition period from idle to normal or high-speed operation. A throttle valve 45 is mounted in the flange portion I o f the mixture conduit 7. The throttle valve is fixed.to,a shaft 46 rotatably mounted in the flange. Fixed to .the shaft is a controllever 47 for manually opening and closing the throttle. In the closed or idle position the throttle is controlled by an adjusting screw 48 engaging a stop 49 on the flange. The Wide-open or high-speed position of the throttle valve l5 is similarly limited by a stop .50 on the lever 47 engaging a stop 51 on theflange. 1. .In the idle or closed position, an edge of the throttle valve 45 is adjacent the idle port 41 as illustrated in the draw ings. During idle operation, a small amount of air' i's permitted to pass around the throttle, which is nottightly seated in the mixture conduit. Other methods of ad mitting air downstream of the throttle during idling are equally applicable.

One or more inside vents '55 connect the fuel reservoir 26 and the inside of the air horn 8tto maintain substantially the same pressure conditions in theair horn and in the fuel reservoir, thereby aiding in calibration of the carburetor and, in cooperation with suitable outside vents 56,-sweeping vapors from the reservoir. -To simplify. the drawing, ,only one inside and one outside vent are shown, but more and in some carburetors outside vents may be eliminated. A check valve 58 is provided in the inside vent 55, and includes a cylindrical housing '59 and a ball 60 which seats in a frustoconical end portion 61 of the housing. The other end of the housing is inturned, as at 62, to prevent the ball from leaving the housing. The check valve housing 59 is preferably formedof brass, and the ball 60 of aluminum. The ball is of such Weight that, during idle operation, the ball is seated in the housing, as'best illustrated in -Figs. 1 and 3, but the ball is sufliciently light that, during normal or high-speed opera- ;tion, when the suction in the air horn portion of mixture conduit 7 is substantially higher, the ball will be drawn ofi its seat permitting fuel vapors to escape through the inside vent 55. During idle operation, when the may be provided, if desired,

suction in the air horn 8 is relatively low, the ball will beseated as illustrated in Fig. 1. However, should the fuel pressure in the reservoir 26 tend to become exceedingly high, it may escape through the outside vent 56. An upper outside vent opening is formed in a cover 64 which encases linkage mechanism for controlling the metering rods, accelerating pump, etc.

7 Fuel in the fuel reservoir 26 will tend to vaporize and form a relatively high pressure in the reservoir because of heat transmitted to the fuel from a hot engine, especially at idle, when temperatures are higher. When such fuel vapors are allowed to enter the air horn 8 during idle operation, they mix with the air, forming a fuel-air mixture, and when this mixture passes downstream of the throttle 45 and mixes with the small ,quantity of idle fuel from port 41 and orifice 42, the resultant mixture is too rich, producing rough engine operation. As the check valve ball 60 is seated during idle because of the smaller pressure diflerential between the reservoir 26 and the air horn 8 than during normal operation, the ball remains seated, closing the inside vent and preventing fuel vapors from entering the air horn.

Although this invention has been described with' reference to particular features and embodiments, various changes will be apparent to one skilled in the art, and the invention istherefore not to be limited to such features or embodiments except as set forth in the appended claims.

I claim: A 1. In a carburetor, a mixture conduit including an air horn, a fuel reservoir having a portion above the rlormal level of said fuel, a passageway connecting said reservoir above said normal fuel level with said air horn, and valve means opening communication between said reservoir and said air horn responsive to a relatively high suction in said air horn as during normal operation, and closing communication between said reservoir and said airhorn responsive to a relatively low suction in said horn as during idle operation. 2 In a carburetor, a mixture conduit including an air horn, a fuel reservoir having a portion above the normal level of said fuel, a passageway connecting said reservoir above said normal fuel level with said air horn, valve means opening communication between said reservoir and said air horn responsive to a relatively high suction in said air horn as during normaloperation, and closing communication between said reservoir and said air horn responsive to a relatively low suction in said air born as during idle operation, and a vent between said fuel reservoir and the outside of said carburetor to relieve pressure in said reservoir sufficiently high to open communication between said reservoir and said air born.

3. A carburetor including a body, a mixture conduit extending through said body and terminating in an air intake at one end and a mixture outlet at the opposite end, said mixture outlet being adapted for attachment to the intake of an internal combustion engine to supply a burnable mixture to operate the engine, a movable throttle valve in said mixture conduit; controlling said mixture outlet adapted when open'beyond a. range of positions for supplying a mixture sufficient for engine idle speed to communicate suction produced by the pumping action of the engine to said mixture conduit above said throttle valve, a fuel nozzle in said mixture conduit, a fuel reservoir supplying fuel to said fuel nozzle, and an inside vent system for said fuel reservoir comprising a passage between said reservoir and said mixture conduit opening adjacent said air intake, a check valve means controlling said passage and arranged to prevent flow from said mixture conduit to said reservoir and to open to permit flow from said passage to said mixture conduit by a diiferential in air pressures created by engine pumping action in said mixture conduit when said throttle is open beyond its range of positions for supplying a-mixture sufiicient for engine idle speeds only, and a vent for supplying atmosphen'cpressure to said valve means to provide the valve actuating force when said throttle is opened beyond an idle range of positions so that suction exists in said mixture conduit above said throttle valve.

4. A carburetor including a body, a mixture conduit extending through said body and terminating in an air intake at one end and a mixture outlet at the opposite end, said mixture outlet being adapted for attachment to theintake of an internal combustion engine to supply a burnable mixture to operate the engine, a movable throttle valve in said mixture conduit controlling said mixture outlet and adapted when open beyond a range of positions for supplying a mixture suflicient for engine idle speed to communicate suction produced by the pumping action of the engine to said mixture conduit above said throttle valve, a fuel nozzle in said mixture conduit, a fuel reservoir for supplying fuel to said fuel nozzle, and an inside vent system for said fuel reservoir comprising a passage extending between said reservoir and said mixture conduit adjacent said air intake, a check valve means controlling said connecting passage and arranged to prevent flow from said mixture conduit to said reservoir and to open to permit a flow from said reservoir through said passage to said mixture conduit when a differential in air pressures is created by engine pump ing action in said mixture conduit by opening said throttle beyond its range of positions for supplying a mixture sufficient for engine idle speed, and an outside vent for said fuel reservoir having a connection with said connecting passage adjacent said reservoir for supplying atmospheric pressure to said reservoir and to said valve means to provide the valve actuating force when said throttle is opened beyond an idle range of positions so that suction exists in said mixture conduit above said throttle valve.

5. A carburetor including a body, a mixture conduit extending through said body and terminating in an air intake at one end and a mixture outlet at the opposite end, said mixture outlet being adapted for attachment to the intake'of. an internal combustion engine to supply a burnable mixture to the engine, a movable throttle valve in said mixture conduit controlling the mixture outlet and adapted when open beyond a range of positions for supplying a mixture sufficient for engine idle speeds to communicate suction produced by the pumping action'of the engine to said mixture conduit above said throttle valve, a fuel nozzle in said mixture conduit, a fuel reservoir for supplying fuel to said fuel nozzle, and an inside vent system for said carburetor comprising a passage between said reservoir and said mixture conduit, adjacent said air intake, a check valve means controlling said passage including a valve cage mounted in a vertical position and having a valve seat at its lower end, a light weight ball movable within said valve cage between said seat and a valve stop at the upper end of said cage, said check valve being arranged to prevent flow from said mixture conduit to said reservoir and to open to permit flow through said passage from said reservoir to said mixture conduit when a diiferential in air pressures is created by engine pumping action in said mixture conduit by opening said throttle beyond its range of positions for supplying a mixture suflicient for engine idle speeds, and an outside vent for said fuel reservoir having a flow capacity less than said inside vent and arranged to supply atmospheric pressure to said ball check valve means to provide the actuating force when said throttle is opened beyond an idle range of positions so that suction exists in said mixture conduit above said throttle valve.

References Cited in the file of this patent UNITED STATES PATENTS Chandler et al. Feb. 22, 1938 Ball et al. Dec. 5, 1939 Mosely et al Apr. 2 0, 1943 Winkler Oct. 28, 1952 Olson Sept. 9, 1958 

